1. Field
This document relates to a thin film transistor, a fabricating method of a thin film transistor, and a display device using the same.
2. Related Art
With the development of the information technology, the market of display devices, that is, connection media between users and information has been expanded. In line with this trend, the use of a flat panel display (FPD), such as a liquid crystal display (LCD), an organic light emitting diode (OLED), and a plasma display panel (PDP), has increasing. Of these, a liquid crystal display, which can implement high resolutions, can be miniaturized and made and can have a large screen size, has been widely used.
Some of the above-mentioned display devices display an image by being driven by thin film transistors formed on a substrate and data stored in capacitors. The thin film transistor may include a gate, a semiconductor layer, a source, and a drain which are formed on a substrate.
Representative display devices driven by thin film transistors include an organic light emitting display and a liquid crystal display. The organic light emitting display is classified as a self-luminous display device, and the liquid crystal display is classified as a light-receiving type display device.
Each of these display devices may have a normal transistor that operates by a voltage supplied to the gate during a thin film transistor formation process and a phototransistor that operates by a channel formed by an external light. Herein, the phototransistor, which is a sensor, is configured circuitally so as to adjust the luminance of a panel by external light.
Conventionally, in a thin film transistor process, an additional process, such as the formation of a doping mask, is performed to dope source and drain regions of a transistor with impurities during the formation of a normal transistor and a phototransistor. In this case, an alignment process for covering a channel region by a mask has to be performed, and this leads to a decrease in production yield in the manufacture of a thin film transistor. Therefore, a solution for this problem is required.